The next two Sundays, June 17 and 24, appear to be the most worrisome dates on the calendar for park officials when up to a million annual passholders — in addition to regular park visitors — could inundate the Anaheim theme park.

"We know many guests have been waiting to experience the newly expanded resort," Disneyland spokeswoman Melissa Britt said. "We expect this to be a popular time."

With up to 100,000 visitors expected at the two-park resort on those days, Disney California Adventure could be forced to shut its gates and direct fans to Disneyland, according to David Koenig, "Mouse Tales" author and MousePlanet blogger.

The next two Sundays stand out because they are the last weekend dates when most annual passholders can visit the park following the Friday grand opening of Cars Land. Fans with the Southern California annual passes will only have eight days to see the new themed land before a seven-week blackout period kicks in for most of the summer. Those days — June 17-19 and June 24-28 — would be particularly good times to avoid DCA.

In anticipation of the crowds, Disney theme park employees will be required to park at Anaheim Stadium, Honda Center and GardenWalk on June 17 and 24 to open up additional parking spaces for visitors in employee lots on Katella Avenue and Ball Road.

Additionally, Disney employees won't be able to sign in family members to either theme park this summer as a result of the expected surge in visitors, according to an internal memo obtained by Koenig.

In an effort to trim the ranks of the estimated 1-million annual passholders, Disneyland recently raised the price of the unlimited premium annual pass by $150, a 30% jump from $499 to $649.

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